firmware/main.c

   1 #include <avr/interrupt.h>
   2 #include <avr/io.h>
   3 #include <avr/power.h>
   4 #include <avr/sleep.h>
   5 #include <avr/wdt.h>
   6 #include <util/delay.h>
   7
   8 #include "logging.h"
   9
  10 #define N_STEPS 5
  11 static unsigned char steps[] = { 60, 85, 121, 171, 242 };
  12 static unsigned char intensity = 0;
  13
  14 static void timer_init()
  15 {
  16         power_timer1_enable();
  17
  18         DDRB |= _BV(PB4);
  19
  20         TCCR1 = _BV(CS10); // clk/1 = 1 MHz
  21         // TCCR1 = _BV(CS11) | _BV(CS13); // clk/512 = 2 kHz
  22         GTCCR = _BV(COM1B1) | _BV(PWM1B);
  23         OCR1C = 255;
  24         OCR1B = 0;
  25 }
  26
  27 static void set_pwm(unsigned char pwm)
  28 {
  29         OCR1B = pwm;
  30 }
  31
  32 static void adc_init()
  33 {
  34         power_adc_enable();
  35
  36         ADCSRA = _BV(ADEN) | _BV(ADPS1) | _BV(ADPS0); // clk/8 = 125 kHz
  37         ADMUX = _BV(REFS1) | _BV(MUX1) | _BV(MUX0); // 1.1V ref., PB3 single-ended
  38         DIDR0 = _BV(ADC3D);
  39 }
  40
  41 static void status_led_init()
  42 {
  43         DDRB |= _BV(PB2);
  44         PORTB &= ~_BV(PB2);
  45 }
  46
  47 static void status_led_on()
  48 {
  49         PORTB |= _BV(PB2);
  50 }
  51
  52 static void status_led_off()
  53 {
  54         PORTB &= ~_BV(PB2);
  55 }
  56
  57 static unsigned char status_led_is_on()
  58 {
  59         return PORTB & _BV(PB2) ? 1 : 0;
  60 }
  61
  62 static void buttons_init()
  63 {
  64         DDRB &= ~(_BV(PB0) | _BV(PB1)); // set as input
  65         PORTB |= _BV(PB0) | _BV(PB1);   // internal pull-up
  66
  67         GIMSK &= ~_BV(PCIE); // disable pin-change IRQs
  68         PCMSK = 0; // disable pin-change IRQs on all pins of port B
  69 }
  70
  71 static void buttons_susp()
  72 {
  73         buttons_init();
  74
  75         GIMSK |= _BV(PCIE);
  76         PCMSK |= _BV(PCINT0) | _BV(PCINT1);
  77 }
  78
  79 static unsigned char buttons_pressed()
  80 {
  81         return (
  82                 (PINB & _BV(PB0) ? 0 : 1)
  83                 |
  84                 (PINB & _BV(PB1) ? 0 : 2)
  85         );
  86 }
  87
  88 #define WAKEUP_POLL 100 // msec
  89 #define WAKEUP_LIMIT 5  // times WAKEUP_POLL
  90
  91 static unsigned char buttons_wait_for_release()
  92 {
  93         uint16_t wake_count = 0;
  94
  95         do {
  96                 if (++wake_count > WAKEUP_LIMIT)
  97                         status_led_on(); // inform the user
  98
  99                 _delay_ms(WAKEUP_POLL);
 100         } while (buttons_pressed());
 101
 102         status_led_off();
 103
 104         return wake_count > WAKEUP_LIMIT;
 105 }
 106
 107 ISR(PCINT0_vect)
 108 {
 109         // empty - let it wake us from sleep, but do nothing else
 110 }
 111
 112 static void wdt_init()
 113 {
 114         WDTCR = _BV(WDIE) | _BV(WDP1); // interrupt mode, 64 ms
 115 }
 116
 117 static void wdt_susp()
 118 {
 119         wdt_disable();
 120 }
 121
 122 static void hw_setup()
 123 {
 124         power_all_disable();
 125
 126         timer_init();
 127         adc_init();
 128         status_led_init();
 129         wdt_init();
 130 }
 131
 132 static void hw_suspend()
 133 {
 134         ADCSRA &= ~_BV(ADEN); // disable ADC
 135         TCCR1 = 0; // disable T/C 1
 136
 137         status_led_init();
 138         buttons_susp();
 139         wdt_susp();
 140
 141         power_all_disable();
 142 }
 143
 144 static volatile unsigned char wdt_timer_fired;
 145
 146 ISR(WDT_vect) {
 147         wdt_timer_fired = 1;
 148 }
 149
 150 static void power_down()
 151 {
 152         hw_suspend();
 153
 154         do {
 155                 // G'night
 156                 set_sleep_mode(SLEEP_MODE_PWR_DOWN);
 157                 sleep_enable();
 158                 sleep_bod_disable();
 159                 sei();
 160                 sleep_cpu();
 161
 162                 // G'morning
 163                 cli();
 164                 sleep_disable();
 165
 166                 // allow wakeup by long button-press only
 167         } while (!buttons_wait_for_release());
 168
 169         // OK, wake up now
 170         hw_setup();
 171 }
 172
 173 static void button_one_pressed()
 174 {
 175         if (intensity > 0) {
 176                 set_pwm(steps[--intensity]);
 177         } else {
 178                 power_down();
 179         }
 180 }
 181
 182 static void button_two_pressed()
 183 {
 184         if (intensity < N_STEPS-1) {
 185                 set_pwm(steps[++intensity]);
 186         }
 187 }
 188
 189 static unsigned char button_state, button_state_time;
 190
 191 static void timer_check_buttons()
 192 {
 193         unsigned char newstate = buttons_pressed();
 194
 195         if (newstate == button_state) {
 196                 if (newstate && button_state_time < 4)
 197                         ++button_state_time;
 198                 return;
 199         }
 200
 201         if (newstate) {
 202                 button_state = newstate;
 203                 button_state_time = 0;
 204                 return;
 205         }
 206
 207         // just released
 208         switch (button_state) {
 209         case 1: button_one_pressed();
 210                 break;
 211         case 2: button_two_pressed();
 212                 break;
 213         default: // ignore when both are preseed
 214                 break;
 215         }
 216
 217         button_state = newstate;
 218 }
 219
 220 static unsigned char blink_on_time, blink_off_time, n_blinks;
 221 static unsigned char blink_counter;
 222
 223 static void timer_blink()
 224 {
 225         if (blink_counter) {
 226                 blink_counter--;
 227         } else if (status_led_is_on()) {
 228                 status_led_off();
 229                 blink_counter = blink_off_time;
 230         } else if (n_blinks) {
 231                 --n_blinks;
 232                 status_led_on();
 233                 blink_counter = blink_on_time;
 234         } else {
 235                 n_blinks = intensity + 1;
 236                 blink_on_time = 0;
 237                 blink_off_time = 2;
 238                 blink_counter = 10;
 239         }
 240 }
 241
 242 int main()
 243 {
 244         log_init();
 245
 246         power_down();
 247
 248 #if 0
 249         ADCSRA |= _BV(ADSC);
 250         while (!(ADCSRA & _BV(ADIF)))
 251                 ;
 252         log_word(ADCW);
 253         ADCSRA |= _BV(ADSC);
 254         while (!(ADCSRA & _BV(ADIF)))
 255                 ;
 256         log_word(ADCW);
 257         log_flush();
 258 #endif
 259         sei();
 260
 261         // we try to be completely IRQ-driven, so just wait for IRQs here
 262         while(1) {
 263                 cli();
 264                 set_sleep_mode(SLEEP_MODE_IDLE);
 265                 sleep_enable();
 266                 // keep BOD active, no sleep_bod_disable();
 267                 sei();
 268                 sleep_cpu();
 269                 sleep_disable();
 270
 271                 if (wdt_timer_fired) {
 272                         wdt_timer_fired = 0;
 273                         timer_check_buttons();
 274                         timer_blink();
 275                 }
 276         }
 277 }